1--- 2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 3SPDX-License-Identifier: curl 4Title: CURLOPT_FTPPORT 5Section: 3 6Source: libcurl 7Protocol: 8 - FTP 9See-also: 10 - CURLOPT_FTP_USE_EPRT (3) 11 - CURLOPT_FTP_USE_EPSV (3) 12--- 13 14# NAME 15 16CURLOPT_FTPPORT - make FTP transfer active 17 18# SYNOPSIS 19 20~~~c 21#include <curl/curl.h> 22 23CURLcode curl_easy_setopt(CURL *handle, CURLOPT_FTPPORT, char *spec); 24~~~ 25 26# DESCRIPTION 27 28Pass a pointer to a null-terminated string as parameter. It specifies that the 29FTP transfer should be made actively and the given string is used to get the 30IP address to use for the FTP PORT instruction. 31 32The PORT instruction tells the remote server to do a TCP connect to our 33specified IP address. The string may be a plain IP address, a hostname, a 34network interface name (under Unix) or just a '-' symbol to let the library 35use your system's default IP address. Default FTP operations are passive, and 36does not use the PORT command. 37 38The address can be followed by a ':' to specify a port, optionally followed by 39a '-' to specify a port range. If the port specified is 0, the operating 40system picks a free port. If a range is provided and all ports in the range 41are not available, libcurl reports CURLE_FTP_PORT_FAILED for the 42handle. Invalid port/range settings are ignored. IPv6 addresses followed by a 43port or port range have to be in brackets. IPv6 addresses without port/range 44specifier can be in brackets. 45 46Examples with specified ports: 47 48~~~c 49 eth0:0 50 192.168.1.2:32000-33000 51 curl.se:32123 52 [::1]:1234-4567 53~~~ 54 55We strongly advise against specifying the address with a name, as it causes 56libcurl to do a blocking name resolve call to retrieve the IP address. That 57name resolve operation does **not** use DNS-over-HTTPS even if 58CURLOPT_DOH_URL(3) is set. 59 60Using anything else than "-" for this option should typically only be done if 61you have special knowledge and confirmation that it works. 62 63You disable PORT again and go back to using the passive version by setting 64this option to NULL. 65 66The application does not have to keep the string around after setting this 67option. 68 69# DEFAULT 70 71NULL 72 73# EXAMPLE 74 75~~~c 76int main(void) 77{ 78 CURL *curl = curl_easy_init(); 79 if(curl) { 80 CURLcode res; 81 curl_easy_setopt(curl, CURLOPT_URL, 82 "ftp://example.com/old-server/file.txt"); 83 curl_easy_setopt(curl, CURLOPT_FTPPORT, "-"); 84 res = curl_easy_perform(curl); 85 curl_easy_cleanup(curl); 86 } 87} 88~~~ 89 90# AVAILABILITY 91 92Port range support was added in 7.19.5 93 94# RETURN VALUE 95 96Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, or 97CURLE_OUT_OF_MEMORY if there was insufficient heap space. 98
